A Case Report of Serotonin Syndrome in a Patient on Selective Serotonin Reuptake Inhibitor (SSRI) Monotherapy

Abstract

Introduction: Paroxetine is a selective serotonin reuptake inhibitor (SSRI) with several indications, one of which is for depression. We present a case of probable paroxetine-induced serotonin syndrome. Case Summary: A 21-year-old female with a history of generalized anxiety disorder and major depression presented with increased depressive symptoms over several months while taking fluoxetine 20 mg daily. Fluoxetine was discontinued without taper and replaced with paroxetine 10 mg daily, along with hydroxyzine 50 mg twice daily as needed for anxiety. Within a week of starting the paroxetine, the patient reported increased anxiety, insomnia, and constant shaking. The paroxetine continued to be uptitrated over a 3-week period to a dose 30 mg due to unremitting depressive symptoms. One month later, the patient presented with tachycardia, generalized body aches, extreme fatigue, weakness, uncontrollable twitching, tremor, and hyperreflexia. A widespread burning sensation accompanied by random hot flashes without diaphoresis was also noted. Serotonin syndrome was diagnosed using the Hunters criteria. Paroxetine was discontinued, and the patient’s physical symptoms resolved within a week. Discussion: To date, only 5 cases of serotonin syndrome have been reported in patients receiving SSRI monotherapy at recommended therapeutic doses.

https://promedsci.org/articles/Propofol%20as%20a%20Rare%20Cause%20of%20Serotonin%20Syndrome

“…SSRI monotherapy has been described through case reports but is very rare [6]. This syndrome occurs in 14-16 percent of people who overdose on SSRIs [7]. Serotonin is difficult to diagnose as symptoms are nonspecific and have many mimickers.…”

Selective Serotonin Reuptake Inhibitors and Adverse Effects: A Narrative Review

“…One case reported moderate serotonin syndrome involving hyperreflexia and ankle clonus in an adult male on sertraline monotherapy [96]. Most other cases of serotonin syndrome with SSRI monotherapy have involved overdose or switching SSRI therapy without crosstitration [97][98][99]. To prevent serotonin syndrome in patients on SSRIs, providers should exercise caution when combining, switching, or discontinuing these drugs [100].…”

Serotonin syndrome

“…Selective serotonin reuptake inhibitors (SSRIs) are among the first-line medications used to treat depression, largely due to their efficacy and tolerability 13. The SSRI class includes citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline.…”

“…1 Of note, in rare cases, serotonin syndrome has been associated with monotherapy of a serotonergic agent. 13 The medications discussed in this article are the most documented contributors to serotonin syndrome. However, this article doesn't contain a comprehensive collection of all known compounds that can cause serotonin syndrome.…”

“…Selective serotonin reuptake inhibitors (SSRIs) are among the first-line medications used to treat depression, largely due to their efficacy and tolerability. 13 The SSRI class includes citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline. As the name implies, these medications selectively inhibit reuptake of serotonin, which allow for more serotonin in the synaptic gap and enables the post synaptic receptors to become more sensitive to the remaining serotonin.…”